Loom let-offs



June 1966 w. J. ROTHFUSS ETAL 3,255,784

LOOM LET-OFFS 4 Sheets-Sheet 1 Filed Oct. 27, 1964 Fl GI INVENTORS WILLIAM J. ROTHFUSS WALTER ENGELS CARLOS L. OWENS BY ,6? 3 M ATTORNEY June ,1966 w. J. ROTHFUSS ETAL 3,255,784

LOOM LET-OFFS 4 Sheets-Sheet 2 Filed 001;. 27, 1964 INVENTORS WILLTAM J. ROTHFUSS WALTER ENGELS CARLOS L. OWENS K V fiwwgl ATTORNEY June 14, 1966 w. J. ROTHFUSS ETAL 3,255,784

LOOM LET-OFFS Filed Oct. 27, 1964 4 Sheets-Sheet 3 FIG?) INVENTORS WILLIAM J. ROTHFUSS WALTER ENGELS CARLOS L OWENS ATTORNEY June 14, 1966 W. J. ROTHFUSS ETAL 4 Sheets-Sheet 4 49 INVENTORS um-mum. 46 WILLIAM J. ROTHFUSS O 1 j 53 5 54 I 47 WALTER ENGELS FIG 5 CARLOS L. OWENS ATTORNEY United States Patent LOOM LET-OFFS William .1. Rothfuss, Greenville, S.C., Walter Engels, Tryon, N.C., and Carlos L. Owens, Greenville, S.C., assignors, by mesne assignments, to Southern Machinery Company, Greer, S.C., a corporation of South Carolina Filed Oct. 27, 1964, Ser. No. 406,713 10 Claims. (Cl. 139110) This invention relates to a let-oif for looms and more particularly to improvements and refinements of the letolfs disclosed in prior United States Patent 2,786,491 to John 0. Hunt and United States Patent 3,156,267, filed March 6, 1963, Felix Ernest Hooper, inventor, copending herewith.

Among the objectives of the invention is to eliminate the need for removing weights from the pivoted weight lever during the unwinding of the warp from the beam.

Another object is to eliminate from the construction as many pivot points as possible, thus avoiding binding caused by misalignment and increasing significantly the sensitivity of the let-off.

Another important object is to provide a shock absorbing connection between the whip roll arm or lever and the weight lever of the let-off thereby substantially eliminating the bouncing of weights caused by oscillations in the warp tension due to beat-up forces to which the warp is subjected from the lay.

A further object of the invention is to provide an improved weight lever with a built-in ratio change from full to empty beam and which is not effected by variations in the position of the tension shaft.

More specifically, an object is to provide a weight lever having an adjustable compensating cam for coaction with a flexible element windable upon the'cam.

Another object is to provide a pivotal mounting for the weight lever which is corrosion-resistant and free turning.

Still another object is to provide a flexible linkage between the weight lever and the whip roll arm or lever which compensates for possible misalignment of hook-up points within practical limits.

Another important object is to provide a shock absorber in the flexible linkagewhich may have its spring tension adjusted during loom operation.

Other objects and advantages of the invention will be apparent during the course of the following detailed description.

In the accompanying drawings:

FIGURE 1 is a fragmentary side elevation of a loom equipped with a let-off according to the invention;

FIGURE 2 is a view of the let-off in end elevation, with parts broken away and parts in section;

FIGURE 3 is a fragmentary vertical section taken on line 33 of FIGURE 1;

FIGURE 4 is a vertical section taken on line 44 of FIGURE 3;

FIGURE 5 is a fragmentary horizontal section taken on line 55 of FIGURE 1;

FIGURE 6 is an enlarged fragmentary cross section taken on line '66 of FIGURE 4; and

FIGURE 7 is a fragmentary side elevation of a modified form of Weight lever, cam and associated elements.

In the drawings, wherein for. the purpose of illustration are shown preferred embodiments of the invention, attention is directed first to FIGURES 1 through 6 which disclose a preferred embodiment.

In these figures, the numeral 10 designates one frame end of a conventional weaving loom, it being understood that the loom includes a substantially identical opposite frame end, not shown. The frame end 10 carries a rigid bearing bracket 11 fixed thereto upon which the arbor 12 of the usual loom beam 13 is journaled for 3,255,784 Patented June 14, 1966 rotation. The other end of the arbor 12, not shown, is supported in a similar manner by a like hearing bracket on the other loom frame end.

The loom includes the usual whip roll 14 over which the warps 15 pass under tension during gradual unwinding from the loom beam. The Whip roll is cradled on whip roll mounting arms 16, carried by shafts 17, rockably mounted on bracket extensions 18, rigid with the loom frame ends. Whip roll levers 19 are adjustably rigidly secured to the rockable shafts 17 and may have their angular relationships to the arms 16 varied when required. The levers 19 are conventional and are connected up with the let-01f in a manner to be described. The whip roll 14 and the levers 19 are swingable vertically upon the axes of the shafts 17.

The improved let-01f constituting the invention comprises a main mounting plate 20 upon which the working components of the let-off are bodily mounted. The mounting plate 20 is formed as a rigid casting and will not bend or deflect under forces to which it is subjected during let-off operation. The mounting plate 20, FIG- URE 2, has an opening 21 formed therethrough for a cylindrical projection 22 of an enlargement 23, forming an integral part of a bracket 24 which is securely bolted at 25 to the adjacent loom frace end 10. The mounting plate 20 is secured in the desired angular relation to the bracket 24 by set screws 26 extending through a flange 27 on the mounting plate 20 and bearing against the underside of enlargement 23. This basic construction is shown and described in United States Patent 2,786,491, issued March 26, 1957, to John 0. Hunt and need'not be further described herein.

The mounting plate 20 has upper bearings 28 and 29 integral therewith, upon which is journaled for rotation an input shaft 30, carrying a worm gear 31, driven by a Worm 32 which rotates continuously during loom operation under influence of a chain 33 and sprocket gear 34, FIGURE 2, driven by the cam shaft of the loom. Consequently, the worm gear 31 is continuously driven and the input shaft in turn is continuously driven so long as the worm gear is clutched to the input shaft 30, as shown in FIGURE 1, and fully described in said prior United States Patent 2,786,491.

Similarly, an output shaft 35 is journaled for rotation near the lower end of the mounting plate 20 by means of additional bearings 36 and 37, integral with the mounting plate. The shafts 30 and 35 are parallel. Power is transmitted from the input shaft 30 to the output shaft 35 by means of adjustable cone pulleys 38 and 39 on the shafts 30 and 35 respectively, as fully described in said prior Patent 2,786,491. The output shaft 35 carries a worm 40, meshing with and driving a worm gear 41 on a let-ofl shaft 42, which let-01f shaft carries a spur pinion 43, meshing with and driving a large spurgear 44, rigid with the loom beam 13 and turning the latter. All of this construction is fully shown and described in the aforementioned United States patent and need not be dealt with in further detail herein for a proper understanding of this invention.

A preferably stainless steel weight lever pivot shaft 45 is held Within a sturdy bearing 46 formed integral with the mounting plate 20 near the left-hand side thereof, FIGURE 1. The pivot shaft 45 is located somewhat above the output shaft 35, as shown. The pivot shaft 45, as best shown in FIGURES 3 and 5, projects beyond the opposite sides of the mounting plate 20 and beyond the opposite ends of the bearing 46 for the reception and support of a bearing hub 47 and a cam 48, which elements form integral parts of a rigid Weight lever 49 shown in FIGURE 5, for example. The weight lever 49 includes a weight supporting arm 50 having plural notches 51 from which weights 52 are suspended .by a suitable hanger 53. The weight lever 49 further includes a bifurcated or U-shaped yoke portion 54 having side parallel arms 55 and 56 carrying the cam'48 and bearing hub 47, respectively. The hub 47 and cam 48 preferably have Within their coaxial bores bushings 57 formed of nylon and receiving the stainless steel pivot shaft 45. The arrangement provides a corrosion-free and low friction pivot for the weight lever 49 upon the main mounting plate 20. As shown in FIGURE and also in FIGURE 4, the yoke portion 54 of the weight lever straddles the mounting plate 20 and bearing 46, whereby the parts 47 and 48 are arranged immediately upon opposite sides of the mounting plate. The construction forms a pivotal mounting for the important weight lever which has no tendency to twist or bind.

Formed integral with the bearing hub 47 and projecting .thereabove is a short lever extension 58, pivotally connected at 59 with an adjustable length link 60. The link 60 is in turn connected with the lower end of a depending lever arm 61, pivotally mounted at 62 upon the main mounting plate 20. An upstanding forked, lever 63 is rigid with the depending lever arm 61 to form a control lever means which is bodily carried thereby on the pivot 62 engages a thrust element 64 on the adjustable section of cone pulley 38 for shifting the same axially on the input shaft 30.

A depending forked lever 65 rigid with the bearing hub 47 of weight lever 49 similarly forms another control lever means which engages a thrust element 66 on the shiftable section of cone pulley 39 to effect axial movernent thereof on the output shaft 35. Consequently, movement of the weight lever 49 on its pivot 45 causes direct and simultaneous movement of the levers 63 and 65 to directly adjust the variable diameter cone pulleys 38 and 39 in order to produce the mode of operation disclosed in the aforementioned prior United States patent.

As a significant improvement over the prior art, the whip roll lever 19 is connected with the weight lever 49 by a novel adjustable and resilient connection forming an important feature of the invention. This connecting means embodies a flexible cable 67 having its lower end portion wrapped upon the aforementioned cam 48 of weight lever 49. In the preferred embodiment of the invention, the cam 48 is cylindrical and concentric with the axis of the weight lever pivot shaft 45. The concentric cam 48 may be considered to be an eccentric or spiral cam having zero eccentricity. The lower extremity of cable 67 is securely clamped to a fiat side 68 of the cam 48 by means of a clamping plate 69 and screw 70, as shown. The upper end portion of cable 67 is connected with a shock absorber unit 71 including a tubular housing 72 having a side pin 73 rigid therewith and pivotally spring washer. The stack of washers 74 thus bear resiliently the force or tension on the cable 67. The tension of the shock absorber or the stiffness thereof may be adjusted by means of a screw 78 which engages the head 76, FIGURE 6.

The general mode of operation of the control means of the let-off for feeding the warps 15 at a constant linear rate and under constant tension remains the same as described in United States Patent 2,786,491 and need not be repeated in detail herein. The weights 52 on the weight lever 49 constantly tend to turn the weight lever in one direction on the pivot shaft 45. This action directly activates the lever 65 and also the lever 63 tending to increase the effective diameter of pulley 39 and decrease the diameter of pulley 38. Constantly counteracting the effect of weights 52 is the action of the whip roll 14 under the tension of the warps 15. This tends to swing the arm '19 in a direction applying tension to the cable 67 through the resilient shock absorber 71. The cable in turn exerts a rotational effect on the cam 48 and weight lever 49 opposite to the effect of the weights and the net result, as described in the aforementioned United States patent, is to keep a substantially constant tension and linear rate of feed on the warps 15 during gradual diminishing of the 'warps on the beam 13.

FIGURE 7 of the drawings shows a modification of the invention, wherein a weight lever 79 corresponding closely to the described lever 49 is mounted upon the aforementioned weight lever shaft 45. All other parts not shown in FIGURE 7 and their functions correspond exactly to the structure shown and described in FIG- URES l-6.

In FIGURE 7, the weight lever 79 has a depending extension 80 for the adjustable mounting of an eccentric or spiral cam 81 which may be adjusted around the shaft 45 and locked in the selected adjusted position by means of a concentric slot 82 and a clamping bolt 83. The cam 81 has a spiral cam face 84 preferably of involute form. The spiral face 84 is on the right-hand side of the cam 81 in FIGURE 7 or on that portion of the cam upon which the cable 67 will be wound when the cam turns in a clockwise direction. The identical cable 67 and clamping means 69 and 70, previously described, may be employed. The spiral cam face 84 radiates successively further away from the axis of shaft 45 progressing in the clockwise direction in FIGURE 7.

The purpose of the spiral cam arrangement in FIGURE 7 is to allow the let-off to compensate automatically for variations in the angle of the warps 15 as the warp diminishes on the beam 13. The resultant force on the whip roll 14 due to warp tension varies both in magnitude and direction as the angle of the warp changes relative to the whip roll during gradual diminishing of the warp on the beam 13. The effective force on the whip roll 14 and therefore the tension force on the cable 67 gradually decreases from full to empty beam conditions. That is to say, these forces decrease as the warp gradually diminishes on the beam 13. During the unwinding of the warp from the beam 13, from full to empty condition, the weight lever 79 swings upwardly from its lowest position about eighteen degrees. During this movement, the spiral cam face 84 coacts with the flexible cable 67 to compensate automatically for the changing magnitude and direction of the resultant force on the whip roll. Thus, the spiral cam 81 on the modified weight lever 79 in FIGURE 7 consitutes a further refinement of the improved let-off depicted in FIGURES l-6. All other parts of the letoff are identical to the corresponding parts shown in FIG- URES 1-6.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.

Having thus described our invention, we claim:

1. In a loom let-off, a mounting plate attachable to a loom frame end, variable transmission means on the mounting plate including an input shaft adapted to be driven from the loom and a let-off shaft adapted for connection with the loom beam to regulate the letting-off of warps therefrom, control means including a weight lever pivoted to the mounting plate, control lever means connected with the weight lever and also connected with the variable transmission means to regulate the latter in response to movements of the weight lever, a spool-like winding element secured to the weight lever to turn therewith on the pivot of the weight lever, a flexible element secured to the spool-like winding element and windable thereon, and a shock absorber connected with the flexible element and adapted for connection with a loom whip roll arm.

2. The invention as defined by claim 1, and wherein the flexible element is a steel cable, and means for detachably clamping one end portion of the cable securely to said winding element.

3. The invention as defined by claim 1, and wherein said shock absorber includes a casing, an element on the casing adapted for pivotal connection to the whip roll arm, a compression spring within the casing adapted to receive one end portion of the flexible element therethrough, an enlarged head on one end of the flexible element engaging one end of said spring, and an adjusting screw on the casing engaging said head and operable to adjust the tension of said spring.

4. The invention as defined by claim 3, and wherein said spring comprises a stack of Belleville spring washers, and abutment means on the casing engaging said stack to retain the stack within the casing.

5. The invention as defined by claim 1, and wherein the spool-like winding element is a spiral cam mounted upon one side of the weight lever adjacent the pivot of the weight lever and adapted to compensate for variations in force transmitted to the loom whip roll by the warp due to changes in the angle of the warp as the warp diminishes on the loom beam.

6. The invention as defined by claim 5, and wherein said spiral cam has a winding face of substantially invo lute form radiating from the pivot of the weight lever and engage-able with said flexible element, said cam having an arcuate adjusting slot concentric with the weight lever pivot and an opening receiving the weight lever pivot element, and means engaging said slot connected with the weight lever to clampingly secure said cam in a selected circumferential position.

7. In a let-off for looms having a mounting plate, variable transmission means on the mounting plate to regulate the letting-off of warps from the loom beam, control means including a bifurcated weight lever straddling an edge portion of the mounting plate, a pivot element on the mounting plate projecting beyond opposite sides thereof and pivotally holding the sides of said bifurcated weight lever, the improvement comprising a cam element secured to one side of the bifurcated weight lever and turning therewith on the axis of said pivot element, a flexible element secured to the cam element and windable upon an exterior cam face thereof, and shock absorber means connected with the flexible element and adapted for connection with a loom whip roll arm.

8. The invention as defined by claim 7, and wherein the cam element is substantially cylindrical in form and secured rigidly to one side of the bifurcated weight lever.

9. The invention as defined by claim 7, and wherein the shock absorber means comprises an adjustable tension spring device.

10. The invention as defined by claim 7, and wherein the cam element has a spirally formed peripheral portion engageable with the flexible element, said cam element adjustable circumferentially on the weight lever, and means to lock the cam element in a selected adjusted position.

References Cited by the Examiner UNITED STATES PATENTS 2,624,184 1/ 1953 Noe 66-86 3,122,172 2/1964 Honegger 139l10 3,156,267 11/1964 Hooper 1391l0 FOREIGN PATENTS 607,069 7/ 1960 Italy.

DONALD W. PARKER, Primary Examiner.

H. S. JAUDON, Assistant Examiner. 

1. IN A LOOM LET-OFF, A MOUNTING PLATE ATTACHABLE TO A LOOM FRAME END, VARIABLE TRANSMISSION MEANS ON THE MOUNTING PLATE INCLUDING AN INPUT SHAFT ADAPTED TO BE DRIVEN FROM THE LOOM AND A LET-OFF SHAFT ADAPTED FOR CONNECTION WITH THE LOOM BEAM TO REGULATE THE LETTING-OFF OF WARPS THEREFROM, CONTROL MEANS INCLUDING A WEIGHT LEVER PIVOTED TO THE MOUNTING PLATE, CONTROL LEVER MEANS CONNECTED WITH THE WEIGTH LEVER AND ALSO CONNECTED WITH THE VARIABLE TRANSMISSION MEANS TO REGULATE THE LATTER IN RESPONSE TO MOVEMENTS OF THE WEIGHT LEVER, A SPOOL-LIKE WINDING ELEMENT SECURED TO THE WEIGTH LEVER TO TURN THEREWITH ON THE PIVOT OF THE WEIGHT LEVER, A FLEXIBLE ELEMENT SECURED TO THE SPOOL-LIKE WINDING ELEMENT AND WINDABLE THEREON, AND A SHOCK ABSORBER CONNECTED WITH THE FLEXIBLE ELEMENT AND ADAPTED FOR CONNECTION WITH A LOOM WHIP ROLL ARM. 